Thursday, February 26, 2015

US River Mapping

Hydro Hierarchy is a map of the largest rivers in the United States and their monthly river flows. Select a river segment on the map and you can view a chart of its 2014 monthly river flow.

The horizontal red line on the bar chart represents the ten year mean monthly flow, which means you can compare each month's river flow to its yearly average. The 2014 drought means that on most river segments most months will be below the ten year average.

The radial chart to the left of the map is a hierarchical representation of the stream network. If you mouse over to the center of the chart you can view river terminations at the ocean or international borders.

Hydro Hierarchy only visualizes rivers and streams with a Strahler stream order classification of four or greater. Andrew Hill has created a map of all United States rivers in which the rivers are colored by the direction of flow. The U.S. Rivers Colored by the Direction they Flow map shows the colored river locations on a black background to create a visually striking map of the United States.

The map uses data from Nelson Minar's Vector River Map, which in turn uses river flow data from
NHDPlus. Andrew has also used the same river data to create another beautiful map. Rivers with Rainfall. This map shows U.S. rivers and rainfall in the last hour. The rain data comes from a National Weather Service data feed.

You can read more about the Hydro Hierarchy map on the Esri Blog and download the source code on the Esri website.